Contaminated Needle Sticks and Microbial Transmission
Syringes are used for a multitude of applications. Typically, a syringe is a simple axial piston pump with a plunger that fits tightly in a cylindrical tube. The plunger can be pulled and pushed along the inside of the tube (or “barrel”), thereby creating a pressure gradient. Many syringes carry a sharp and penetrating hollow needle that is intended to puncture the skin, mucous membrane and internal organs of humans or animals for injection or removal of fluids, aerosols, or particulate suspensions.
Hypodermic syringes when used on patients may become contaminated by dangerous and often lethal microbes. The syringe can transmit the microbes to the administering or assisting physicians, nurses, healthcare workers, and sanitation workers by accidental needle sticks. The U.S. Congress has enacted a “Needlestick Safety and Prevention Act,” Pub. L. 106-430, 114 Stat. 1901-1904 (2000), which makes use of engineered safety devices mandatory.
Hypodermic syringes and needles are responsible for 29% of accidental needle sticks. In addition to the possibility of dangerous infections, accidental needle sticks are also responsible for enhancement of the healthcare cost, which may amount to $3500 for each incident of needle stick injury.
Devices intended to prevent needle sticks are available and include needle covering devices, such as sheaths or sleeves that are pulled on the hypodermic needles after use. Hinged devices or sliding devices that cover the used needles are called “safety” needle devices. Mechanical cutters of needles, pulverizers, and electrical evaporators of needles are all currently used. However, the best protection may be offered by the retractable devices which ensure that the needle is not accessible to injure anyone after the use.
Desirable Characteristics of Devices with Safety Features
Improved engineering controls are often among the most effective approaches to reducing occupational hazards, and therefore are an important element of a needle stick prevention program. Such controls include eliminating the unnecessary use of needles and implementing devices with safety features. A number of sources have identified the desirable characteristics of safety devices [OSHA 1999c; FDA 1992; Jagger et al. 1988; Chiarello 1995; Quebbeman and Short 1995; Pugliese 1998; Fisher 1999; ECRI 1999]. These characteristics include the following:                The device is needleless.        The safety feature is an integral part of the device.        The device preferably works passively (i.e., it requires no activation by the user). If user activation is necessary, the safety feature can be engaged with a single-handed technique and allows the worker's hands to remain behind the exposed sharp end.        The user can easily tell whether the safety feature is activated.        The safety feature cannot be deactivated and remains protective through disposal.        The device performs reliably.        The device is easy to use and practical.        The device is safe and effective for patient care.        
Although each of these characteristics is desirable, some are not feasible, applicable, or available for certain health care situations. For example, needles will always be necessary where alternatives for skin penetration are not available. Also, a safety feature that requires activation by the user might be preferable to one that is passive in some cases. Each device must be considered on its own merits and ultimately on its ability to reduce workplace injuries. The desirable characteristics listed here should thus serve only as a guideline for device design and selection.
Needle Stick Prevention & Infection Control
There are several retractable syringes that are commercially available, e.g., an Integra™ syringe, manufactured by Becton, Dickenson, and Co. (BD) of Franklin Lakes, N.J., a VanishPoint® syringe, manufactured by Retractable Technologies, Inc. (RTI), of Little Elm, Tex., a saf-T-syringes™ syringe, manufactured by Safety Medical International, Inc., of Apopka, Fla., OMI Syringes™, manufactured by Occupational & Medical Innovations (OMI) Ltd., of Slacks Creek, Australia, and Unitract Syringes™, manufactured by Unilife Medical Solutions, of Sydney, Australia. In these examples, a nozzle installed spring surrounding the needle retracts the needle inside the hollow plunger of the syringe. All these syringes require creating a communication between the barrel cavity and the plunger cavity by cutting the rubber stopper or displacing a rubber plug, which has the following shortcomings:                (a) This mechanical operation requires a voluntary act on the part of the user. Such devices are active and user dependent. These devices do not operate passively, which is the preferred mode for ultimate safety of syringes.        (b) The impact of active manipulation of cutting or breaking the rubber seal is transmitted to the needle point while the needle is still in the patient's body.        (c) When the needle is taken out of the patient's body and retraction is initiated, there is danger of aerosol and microbial spread to others during the retraction process.        (d) The retractable needle syringes are not tamper proof, and there are many instances where the contaminated needle, floating free in the plunger cavity of these syringes, can escape and cause needle stick injury and microbial transmission.        (e) They are therefore required to be disposed of in sharps containers, for safe disposal, as are other needles and syringes.        (f) Despite engineered safety imparted to the devices, remain unsafe after use and need disposal in the sharps containers. Disposal in sharps containers is an expensive luxury and is not available, nor affordable, in many countries.        (g) An unscrupulous person can still use these retractable needle syringes and not initiate the retraction, and then re-use them.Unsafe Injections in Developing World        
The accidental needle stick and microbial transmission is the sole problem focused on in the United States, Canada, Australia and Western Europe. Major hazards posed by hypodermic syringes are not addressed by the legislation passed by these countries, including the “Needlestick Safety and Prevention Act” in the United States.
One major hazard is the re-use and improper sterilization of the disposable contaminated syringes. Re-use of syringes is rampant in India, Pakistan, China, Southeast Asian countries and Africa. Several United Nations reports and publications have highlighted this hazard, but a solution is not in sight because often the culprits are those who have responsibility to administer healthcare or unscrupulous workers who permit entry of used syringes into the healthcare supply chain. (“Seventy per cent syringes unsafe in India,” The Hindu, 17 Dec. 2004; Bull World Health Organ, 1999, 77(10):789-800; “Unsafe injections in the developing world and transmission of blood borne pathogens: a review,” Simons L, Kane A, Lloyd J, Saffron M, Kane M. World Health Organization, Geneva, Switzerland.)
Cause of Unsafe Injection is Re-using of Syringes
The existing legislation and education programs have proved futile. Every re-used unsafe syringe already carries a prominent “DO NOT RE-USE” label. Most often glass syringes that can be boiled to sterilize and used are less expensive than disposable sterile plastic syringes. The cost of sterilization in those countries is low in comparison to pre-sterilized disposable syringes which are expensive, and remain expensive because they are not used on a mass scale. Even the disposable plastic syringes are re-used by boiling again and again. Finally the governments of many countries are frustrated and have resorted to syringes that would destroy themselves so that they cannot be re-used. The gravity of the re-use problem compels these governments to totally neglect the more serious and deadly situation of needle stick injury and microbial transmission. AIDS and hepatitis are rampant and growing to epidemic proportions because of this dual malady.
Relevant Re-Use Prevention Art
The irony of the current situation is the fact that although syringes are intended to be disposable, they are not. They are made from plastic that is durable.
Most of the re-use prevention art relies on breaking one of the parts of the syringe, preferably the plunger, by the user voluntarily or in an attempt to re-use. One auto-destruct syringe marketed in India relies on a ring at the nozzle of the barrel which locks the plunger when medicine is injected. The plunger is intentionally made weak. On pulling back for re-use, it breaks. However, the hypodermic needle is still exposed to cause needle stick and spread infection, and culprits will re-use the contaminated needle anyway.
Another auto-destruct syringe used for immunization carries a clip in the barrel. After injection, the clip locks the syringe. The needle is intact and unsafe. Yet another auto-destruct syringe employs a unique plunger-breaking mechanism which is “clinician-activated,” to eliminate any possible re-use of the syringe. This mechanism allows the user to draw the medicine more than once, unlike a single dose injection, and then break the syringe after use. The control is therefore in the user's or clinician's hands, thus eliminating wastage. The needle remains unsafe, to spread blood-borne infections.
Inadequate Sharps Disposal in Developing Countries
About 75% of the world has no reliable system for disposition of used contaminated syringes/sharps. Sharps container service is neither available nor affordable. Even if sharps containers are provided, workers will re-use the syringes rather than using sharps containers, because re-use is more profitable.
Syringe manufacture and distribution is a global business, and there is no way to control the traffic or enforce safety requirements for these devices. Implementation of the use of specific single-use devices is impossible because these two different worlds have different objectives, and different messages. While developed countries strive to protect its people from contaminated needle sticks, the slogan for the developing world is “one syringe, one injection.” Users cannot be relied upon to resolve these problems, and thus there is a need for a universal syringe that will not be under the control of its user for safety and will ensure safety by its own mechanism.